The LIKE condition selects rows by comparing character strings with
a pattern-matching specification. It resolves to true and displays the matched
strings if the left operand matches the pattern specified by the right operand.

The ESCAPE clause is used to search for literal instances of the percent
(%) and underscore (_) characters, which are usually used for pattern matching.

Because the % and _ characters have
special meaning in the context
of the LIKE condition, you must use the ESCAPE clause to search for these
character literals in the input character string.

These examples use the values app
, a_%
, a__
, bbaa1
, and ba_1
.

The condition like
'a_%'
matches app
, a_%
, and a__
, because the underscore (_) in the search
pattern matches any single character (including the underscore), and the percent
(%) in the search pattern matches zero or more characters, including '%' and
'_'.

The condition like
'a_^%' escape '^'
matches only a_%
, because the escape character (^) specifies that the pattern search
for a literal '%'.

The condition like
'a_%' escape '_'
matches none of the values, because the escape character
(_) specifies that the pattern search for an 'a' followed by a literal '%',
which does not apply to any of these values.